1. Field of the Invention
The present invention relates to an ink jet printer head including an ejector unit having a plurality of nozzles each of which ejects a droplet of ink toward a recording medium, and a cover member (e.g., a cover plate) which is fixed via a sealing portion (e.g., a sealing agent) to the ejector unit, and also relates to a method of producing an ink jet printer head.
2. Discussion of Related Art
For example, Document 1 (i.e., Japanese Patent Application Publication No. 2002-067341 A1) or Document 2 (i.e., Japanese Patent Application Publication No. 2002-234144 A1) discloses an ink jet printer head including an ejector unit having a plurality of nozzles each of which ejects a droplet of ink toward a recording medium, and a cover plate which is fixed via a sealing agent to the ejector unit.
More specifically described, the ink jet printer head disclosed by each of the above-indicated two publication documents employs a plurality of ejector units each of which has, in an outer surface thereof, a plurality of nozzles arranged in at least one array; a cover plate which has a plurality of openings and covers the ejector units such that the array of nozzles of each of the ejector units is exposed through a corresponding one of the openings; and a frame member supporting the ejector units and the cover plate. The ink jet printer head is assembled in a state in which the array of nozzles of each one of the ejector units is accurately positioned relative to the array of nozzles of the other ejector unit or units. In this state, a sealing agent is provided, between the cover plate and each of the ejector units, along the periphery of a corresponding one of the openings of the cover plate, so that the cover plate covers the respective outer surfaces of the ejector units. Respective opposite surfaces of the ejector units that are opposite to the respective outer surfaces thereof are covered by a bottom wall of the frame member. When an adhesive is charged into through-holes that are formed through the thickness of the bottom wall of the frame member, the ejector units are fixed, with the adhesive, to the bottom wall in the above-indicated state. Simultaneously, the cover plate is fixed, with the adhesive, to the bottom wall of the frame member.
Although, in the above-described ink jet printer head, the ejector units are fixed to the bottom wall of the frame member, with the adhesive charged via the through-holes formed in the bottom wall, the dimensions and positions of the through-holes are more or less limited in view of the structure and strength of the bottom wall, and accordingly the positions where the adhesive is applied are limited. Thus, the adhesive strength of the ejector units cannot be sufficiently increased.
In addition, in a state before the ejector units and the cover plate are finally fixed with the adhesive to the frame member, the ejector units and the cover plate are just temporarily adhered to each other with the sealing agent only. Therefore, the cover plate and each of the ejector units may be displaced relative to each other and accordingly the sealing agent may flow or move. Consequently defects of adhesion, such as bubbles or uneven adhering, and/or defects of sealing, such as gaps or uneven sealing may occur to those portions of the printer head that are sealed by the sealing agent.